When to Change RO Membrane & Filters? – RO Maintenance Guide

If you are using an RO water purifier then you should know the importance of changing RO Membrane and Filters on time.

The purpose of this post is to tell you how important it is to take good care of the maintenance and service of your RO purifier to keep getting pure and 100% safe drinking water.

When we talk about the maintenance of RO purifiers the first thing that comes to our minds is the replacement of the filters and membranes.

It is essential that you have a basic understanding of the periodic schedule of replacement of filters because filters and Membrane constitute the major parts of any water purifier. And the cost of replacement of filters and membrane is around 80% of total maintenance costs of an RO purifier.

The purpose of this post is not to turn you into some technical expert on RO water purifiers but to give you a fair understanding of when to replace the filters and membrane of your water purifier.

This information helps in –

Making sure that you always get clean, pure and 100% safe water.

Increasing the life of your RO water purifier.

Reducing the maintenance cost.

Avoid being cheated by unethical service technicians.

The question at hand may seem to be very clear and quite straightforward but the answer is not so simple because when we talk about replacing the filter and membrane the approach can’t be ‘one size that fits all’.

Therefore, before we start spilling the beans on when to replace RO membrane and filters, it is important that we first tell you about all the factors on which it all depends.

Below factors should always be taken into account before estimating the good time to change RO membrane or filters.

Level of impurities in the input water.

TDS Level or hardness of the input water.

How much water you purify using your RO purifier.

If the water has very high level of impurities, high TDS level or if you use your RO purifier to purify large quantities of water, then the filters and RO membrane would need to be replaced quite frequently.

The schedule of change of RO membrane and filters that we have put out in the following paragraphs is for an average Indian household of around 4-6 family members.

The RO pre-filter (installed outside the RO water purifier) should ideally be replaced every 3 – 4 months. The replacement interval can be shorter or longer depending upon the quality and quantity of water purified.

The other pre-filters which include the Sediment Filter and Carbon Filter should be changed every 6-12 months depending on how much water you purify and how good or bad the input water is. However, this is just an average and to get the exact time to change them we need to look at filters individually.

When to Change Sediment filter?

Sediment Filter is designed to remove sediment and dirt from the water so your carbon filter and RO membrane doesn’t get clogged prematurely.

Every home might have different amount of sediment in the input water so there is no ‘one size fits all’ answer to tell you how long it should last for you.

It is important to keep the pressure as high as possible going in to the membrane and the sediment filter would only cost a few hundred rupees so it is always recommended to change the Sediment Filter on time. If Sediment filter is not changed on time then the dirt will reach the RO membrane and the membrane will get clogged, this reduces the efficiency and the life of RO Membrane.

If you maintain your Sediment Filter properly, the Carbon Filter and RO Membrane should last a long time.

We recommend that Sediment Filter should be changed at least once a year.

When to Change Carbon filter?

Water from Sediment Filter is passed through the carbon filter (also known as the Activated Carbon Filter), which removes chlorine and other organic contaminants. Carbon filter also filters out the bad odour and unpleasant taste from the water.

Chlorine in water also adversely affects the life of the RO membrane. Activated carbon filter absorbs Chlorine and other organic impurities and thereby extends the life of the RO membrane. It is therefore very important to change the Carbon filter at regular intervals in order to increase the life of RO Membrane and prevent bad odour and bad taste in the purified water.

We recommend replacing your Carbon filter at least once in a year.

When to Change RO Membrane?

RO Membrane is the most vital part of any RO water purifier. RO Membrane is actually the filter that is doing all the work, the Sediment Filter and Carbon Filter are only preparing the water for the RO membrane so it doesn’t get damaged.

If you take good care of the sediment and carbon filters, and replace them at the required intervals then RO membrane only needs to be changed after purification of 4,000 to 6,000 litres of water.

The RO membrane may die early or last longer depending on the TDS of input water. The replacement of RO membrane will be based on the consumption of water, quality of input water and efficiency of sediment filter and carbon filter.

Typically, RO Membranes last for about 2-3 years, however we have seen them go as long as 5 years. Your RO membrane may die earlier if you have really hard water or if you never flush the membrane.

The best way to know when you should replace your RO membrane is to check the TDS level of purified water. You will need a TDS meter like this one for finding out the TDS level. If you don’t already have one, we recommend buying a digital TDS meter to easily find out the TDS in water.

You will know that your RO membrane is starting to go bad when the TDS begins to climb. This can often happen pretty suddenly because of that we recommend changing the RO membrane every 2-3 years.

Please Note: If the input water is very hard or has a high TDS then the RO membrane may need to be replaced more frequently. You should always check the specification of your RO purifier or most accurately that of your RO membrane. For example, if the RO membrane is capable to purify up to 1500 ppm of TDS, purifying input water that has higher than 1500 ppm TDS will reduce its life.

We would like to finish this complete information with an important advice.

We all know RO water purifiers are quite expensive as compared to other types of water purifiers but an absolute necessity to purify high TDS water. The maintenance cost of RO purifiers is also comparatively high because of costly filters and membrane.

Apart from the cost, we also know that RO purifiers result in huge wastage of water as an average RO water purifier produces around 70-80% of waste water.

You should use an RO purifier only when the input water has high TDS (over 500 ppm) and the water doesn’t taste natural.

If the water supply at your home does not meet the above criteria then the initial cost, cost of maintenance, and wastage of water in an RO purifier will overshadow the benefits. For effective purification of low TDS water you can opt for a multi stage UV purifier, which costs less, maintenance cost is less and wastes negligible water.

Thank you for sharing such detailed and very useful information. This will definitely be helpful for people who are using RO purifiers and often remain confused about when to change RO membrane or filters.